Karen Weintraub in Scientific American:
In one type of cancer immunotherapy, immune cells called T cells are removed from the body and engineered to target cells that are only found in cancers. The engineered cells, called chimeric antigen receptor T cells (CAR-Ts), have proved exceedingly effective against some types of blood cancers, particularly acute lymphocytic leukemia. Scientists have now started engineering T cells to attack other disease-related cells.
Cancer was a logical first step for immunotherapies, says Marcela Maus, director of cellular immunotherapy at the Massachusetts General Hospital’s Cancer Center and an assistant professor at Harvard Medical School. The need for life-extending therapies in cancer is indisputable. There is a willingness to take risks to fight tumors that might otherwise be fatal, she says. Doctors are likely to be more cautious in fighting autoimmune diseases, which can be terrible but also have some existing—if imperfect—treatments. Now that the immunotherapy work has proved so successful in cancer, it makes sense to push it into other illnesses, Maus says.
A group led by Aimee Payne, a dermatologist at Penn Medicine, is currently preparing for human trials using reengineered T cells to treat an autoimmune-triggered skin disease called pemphigus. In one subform of the affliction that affects about 4,000 Americans, the immune system produces antibodies against proteins that hold the skin together, resulting in painful, debilitating blisters. Payne and her colleagues direct engineered T cells to destroy the immune cells that make these antibodies, and their work has shown promise in animals. Payne says she got the idea for this approach from all the attention successful CAR-Ts were receiving at Penn Medicine. It seemed so simple in retrospect: “You’re like, ‘Why didn’t we think of this earlier?’” she adds.